1. Field of the Invention
The present invention relates generally to an electric motor assembly. More specifically, the present invention concerns an electric motor assembly that includes an endshield having a universal bearing receiving core that can alternatively accept various bearing assemblies to increase design options without requiring additional specialized parts.
2. Discussion of the Prior Art
Those of ordinary skill in the art will appreciate that electric motor assemblies typically include bearings to rotationally support the shaft. There are many different types of bearings, with each type having distinct advantages and disadvantages. Therefore, design requirements often dictate which type of bearing is used in a particular motor assembly. Due in part to the differences in the construction and size of bearing selections, each type of bearing has conventionally required a specialized core or housing in which the bearing is properly positioned for operation.
For example, in a broad range of air moving motors, such as those that would ordinarily power a condenser fan or furnace blower, bearing selection can include at least the options of a self-aligning bearing or a ball bearing. On the one hand, selecting self-aligning bearings may result in quieter operation, as noise generated by the bearing would be undesirably transmitted through the house, but on the other hand, the selection of ball bearings usually results in an assembly that is tougher for handling side loads. Other design considerations may include operating temperature, such as a high temperature requirement for an assembly that will be operating on the roof of a house with hot air coming off of the motor coils. Self-aligning bearings tend to use a lighter weight oil for lubrication purposes and cannot be used in extreme high temperature applications, while ball bearings can use thicker grease for lubrication and can withstand such temperatures.
Conventionally, the selection of one or another type of bearing assembly has required different endshield parts that are individually specialized to accommodate each type of bearing. Even where traditional endshields have attempted to adapt to a more multipurpose construction, such endshields have required complex retaining ring assemblies that are specially tailored for each type of bearing. These systems have lead to the need for extensive inventories of parts to accommodate motor assemblies for varying design considerations.
While such conventional endshield systems have been satisfactory in some respects, those of ordinary skill in the art will also appreciate that the multitude of parts that has been necessary to work with various bearing options is burdensome. Maintaining multiple endshields for different bearings can require die-casting, machining, stocking, shipping, and using two entirely different parts. This has lead to more part variations in machining databases and increases costs, as multiple dies and machining centers are typically required to provide the ability to use either a self-aligning bearing or a ball bearing in a given motor assembly.
The prior art simply does not include an electric motor assembly that can satisfactorily receive and position one of a variety of bearing assemblies without requiring an assortment of specialized endshields or other parts, the production and inventorying of which adds cost and the potential for errors in the assembly of the motor.